Update package dependencies

Author: AArnott

Directory.Build.props

@@ -24,12 +24,12 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="3.3.1" PrivateAssets="all" />
-    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="3.7.0" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.Net.Compilers.Toolset" Version="3.8.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.NETFramework.ReferenceAssemblies" Version="1.0.0" PrivateAssets="all" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="all" />
     <PackageReference Include="Nerdbank.GitVersioning" Version="3.3.37" PrivateAssets="all" />
     <PackageReference Include="Nullable" Version="1.3.0" PrivateAssets="all" />
-    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.164" PrivateAssets="all" />
+    <PackageReference Include="StyleCop.Analyzers" Version="1.2.0-beta.261" PrivateAssets="all" />
   </ItemGroup>
 
   <ItemGroup>

test/Library.Tests/Library.Tests.csproj

@@ -10,7 +10,7 @@
 
   <ItemGroup>
     <PackageReference Include="coverlet.msbuild" Version="2.9.0" />
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.7.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.8.0" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
   </ItemGroup>